People are living longer, and at the same time the cost of health care is rising.

That combination imperils your ability to pay for medical care as you age, so it's important to think about long term health care insurance, especially for people in their 40s and 50s.

The U.S. Department of Health and Human Services estimates that 9 million Americans who are now 65 or older will require long-term care, and that number is expected to increase to 12 million by 2020.

The average annual cost of nursing home care is now $74,806, a figure that varies by region and according to the level of care required.

"The No. 1 misunderstanding people have is that they think Medicare will take care of them," said Sandy Praeger, president-elect of the National Association of Insurance Commissioners (NAIC) and Kansas's insurance commissioner. "Medicare pays significantly less than people think -- only for rehabilitation and only for a short period of time. So families find themselves saddled with hefty long-term fees.

With more dual-income families today there are fewer stay-at-home caregivers, so more elderly people must depend on professional care, she pointed out.

"Consumers who would like to protect their assets, minimize dependence on family members and control how they receive nursing or home care should carefully consider long-term care insurance," Praeger said.

When people become unable to perform activities such as eating, dressing and bathing on their own, long-term care insurance will pay for the services of nursing homes, assisted-living facilities and in-home caregivers. Long-term care insurance covers expenses for people diagnosed with chronic illnesses such as Alzheimer's disease, Parkinson's disease, multiple sclerosis and diabetes.

Standard health insurance policies and Medicare usually do not pay for long-term care expenses associated with these illnesses. State-administered Medicaid programs offer limited long-term care benefits, and only after a person's assets have been depleted. Long-term care insurance can preserve assets. Rates for long-term care are more affordable for people in their 40s and 50s, and it's important to buy a policy before health-threatening conditions such as diabetes set in.

Investigate long-term care coverage if you don't want to rely on others to support you, and you want flexibility in the type of long-term care services you receive.

Make sure you understand what the policy covers and what it doesn't. Make sure any policy includes: An "outline of coverage" that clearly describes the policy's benefits, terms and limitations in detail; a clear description of the elimination period -- the number of days that must be spent in a nursing home or in claims status before the long-term care insurance coverage kicks in; at least one year of nursing home or home health care coverage or both, the right to cancel the policy for any reason within 30 days of purchase and receive a full refund; a guarantee that the policy cannot be canceled or terminated because of the policyholders age or physical or mental health condition; and inflation protection.